1. Field of the Invention
The present invention relates to a complementary division method, a method of producing a mask, and a program, in particular a complementary division method utilized to a pattern formation of a stencil mask used for a lithography process of a semiconductor device, a method of producing a mask, and a program.
2. Description of the Related Art
As a next generation exposure technology instead of photolithography, a projection exposure technology using electron beam has been developed. The projection exposure technology has an electron projection lithography (EPL) technology using accumulated electron beam of around 100 kV to form a mask pattern enlarged with a device pattern at the constant times on a mask similarly to photolithography and use, and a low energy beam proximity projection lithography (LEEPL) technology using low energy electron beam of around 2 kV to form a mask pattern having same time as a device pattern on a mask and use.
H. C. Pfeiffer, Jpn. J. Appl. Phys. 34, 6658 (1995) discloses masks used in the above exposure technology that mask differs from a photomask, is formed on it with a thin film region (membrane) of around 0.1 to 10 μm, and formed on that with a mask pattern as apertures. And these membrane materials have been proposed with silicon, silicon carbonate, and silicon nitride.
In the stencil mask, a pattern having unaperture portions in the middle portion like the doughnut shaped pattern will come out and cannot be formed. Therefore, the pattern has to be divided into a plurality of complementary patterns, formed with the respective pattern at the other portion on the mask or at the another mask, and exposed at several times so as to connect the respective complementary patterns at a wafer.
However, as shown in FIG. 1A, when a thin film 3a is formed with apertures 5a of line-and-space (L/S) patterns and then wet washed, the thin film (struts) between the apertures 5a is loaded such that the struts contact the adjoining struts (beams) when washing. As a result, it suffers from the disadvantage in that the respective adjusting struts deform and do not return to their original formations, as shown in FIG. 1B.
Japanese Unexamined Patent Application No.2001-274072 discloses a technology considering a pattern deformation by washing that the pattern is divided into grid portions having defined dimension. However, it has been a disadvantage that a complimentary division algorithm is complicated. And Japanese Unexamined Patent Application No. 2001-274072 discloses an example of the line-and-space pattern, however a division rules thereof is not disclosed.